Yup! It just has to be a solid color. Also, the official student handbook says that the top and bottom need to be the same color and that you're supposed to only wear white shirts underneath. However, I don't even own a white shirt and wear ALL kinds of colors underneath (esp. during winter) and a few classmates wear darker pants than tops, though that's probably because they avoid laundy. 😀
So as long as you're either wearing scrubs or decent work clothes, they don't car.